Scaling concepts, related to basic physical transport and mixing processes and other ecological
aspects in lakes, are reviewed in an ecohydrodynamic perspective; the length and time scales as
well as the non-dimensional parameters governing the various flow regimes and relevant to these
processes are also presented, emphasizing the influence they have on lake ecosystems. The
hierarchy of length scales is very important in determining both the turbulence structure, and in
affecting the ecological processes occurring in lakes. Most of these scales are defined in terms of
several basic parameters which, when combined properly, yield important dimensionless numbers,
as: Rf, Ri, Pr, T, Ret, Frt, Grt, and Prt, the flux and gradient Richardson numbers, the Prandtl
number, a dimensionless time, and the turbulent Reynolds, Froude, Grasshof and Prandtl numbers,
respectively. A few more dimensionless numbers (as the Lake and Wedderburn numbers, LΝ, W,
etc.) are also useful in characterizing the general dynamic behavior of lakes. Ratios of length or time
scales may also provide similar useful parameters.

The temporal and spatial scaling concepts related to basic physical and ecological lake processes
and the associated non-dimensional parameters that govern the various flow regimes, developed in
lakes and reviewed in Part 1 of our companion paper (Papadimitrakis, 2011), are applied to lakes
Pamvotis and Vegoritis, two water enclosures located in the Northern Greece having different
bathymetry and morphology and forced by dissimilar external conditions. This paper begins with a
description of the interaction of physical and biological processes in lakes (the latter being described
in Part 1) and proceeds with the application of scaling concepts to the above lakes. From these two
applications, several interesting conclusions are drawn by comparing the similarities and differences
shown in the variation, with time, of these important scales and non-dimensional parameters and
how the latter affect the various lake flow regimes.

The effect of temperature increase and more specifically its upper and low level correlates on soil
microbial biomass, activity and N-cycle variables was studied in a Mediterranean shrubland.
Experimental manipulation succeeded in establishing three treatments which, in comparison with the
monthly ambient temperature, displayed an increase in mean monthly temperature by 2.1, 4.9 and
7.4 oC respectively. Also the upper limit temperature values (Tmax), but not the low limit counterparts
(Tmin), differed significantly among the three treatments. Tmax changes seemed to affect directly only
the microbial biomass, while it exerted an indirect effect on the majority of the other soil variables.
With increased Tmax the values of the estimated soil microbial variables (microbial biomass and
activity) increased, while other soil chemical variables, such as the inorganic forms of N, were found
reducing. Organic N was the only variable remaining independent from changing Tmax at any
treatment. The results of this paper indicate that the level of Tmax increase could be crucial for the
structure of the microbial community. A Tmax increase up to 7 oC induced by climate change could
favour the dominance of the soil bacterial populations, while larger increases could be in favour of
the fungal populations.

In the present study seasonal changes of chlorophyll content and storage substances related to the
metabolic response of the widespread, evergreen plant oleander (Nerium oleander) to air pollution
were investigated. Mature leaves of oleander shrubs, grown at five sites of differing levels of air
pollution in the center and the suburbs of the Athens Metropolitan area, were examined during the
course of a year. Soluble sugars, starch and total lipid content of the leaves showed a peak at the
end of the cold season, while a decline was detected during the main growth period. Leaf
chlorophyll content was increased during spring. It seems likely that the level of air pollution in
Athens did not affect the concentration and the seasonal pattern of storage substances at the leaf
level. Elevated chlorophyll content was estimated in the polluted with oxides of nitrogen sites. In
contrast, leaf chlorophyll content declined in sites with ozone pollution.

The effects of different mixture ratios of sewage sludge (SS), organic fraction of municipal solid
waste (OFMSW) and yard trimmings (YT) on the performance of composting process were
investigated in this study. The high water content and the proper carbon/nitrogen ratio make sludge
ideal for this procedure, improving the characteristics of the initial composting mixture. OFMSW and
YT enable the production of a quality product that may be used as a soil conditioner. Therefore, piles
of about 1 m3 were prepared by mixing OFMSW, SS and YT in four different ratios (w/w) [only
OFMSW, OFMSW:SS = 2:1, OFMSW:SS:YT = 3:1:2, and OFMSW:SS:YT = 4:1:2]. The piles were
kept in controlled aerobic conditions for 10 weeks. The temperature of the piles was measured daily
(for the first 4 weeks) and ranged between 60-70 oC, while air was provided to the piles by
mechanical turning. Results showed that the pile OFMSW:SS:GW = 3:1:2 was most beneficial in
composting, since its ability to accumulate and retain heat and achieve high organic matter
degradation. The final compost products contained C/N ratio less than 15 indicating that achieved
mature and stable products. The heavy metal contents in the final composts were several times
lower than regulation limits.

The performance of electrocoagulation using iron electrodes for the removal of hexavalent chromium
from synthetic aqueous solutions and actual industrial electroplating wastewater was studied.
Parameters affecting the electrocoagulation process, such as initial pH, applied current density,
initial metal ion concentration, COD and time of electroprocessing were investigated. The optimum
pH was found to be in the range 4-8. Initial chromium concentrations of 200 – 800 mg L-1 did not
influence its removal rate. Higher concentrations were reduced significantly in relatively less time
than lower concentrations. Increased current density accelerated the electrocoagulation process,
however, on cost of higher energy consumption. Results revealed that best removal was achieved at
a current density 40 mA cm-2. The electrocoagulation process was successfully applied to the
treatment of an electroplating wastewater sample. Its Cr (VI) ion concentration and COD were
effectively reduced under the admissible limits in 50 minutes of electroprocessing.

The last few decades we have witnessed an enormous rise in awareness of the importance of
wetlands. Mathura beel1 has been assumed to take the attention in recent years because of its
ecological significance in terms of flood control, water purification, aquatic productivity, and microclimatic
regulation etc. The aim of this paper is to present a complete scenario of Mathura beel
through different analyses. To materialize the main objective, the water quality monitoring, socioeconomic
analyses, and a perception study on wetland use and wetland threat are considered
separately. In this study, the objective was extended to observe the complete socio-economic status,
and a detailed perceptional study on wetland use, and wetland threat. At the end of the study,
detailed management options have been given to protect and to conserve the economy and the ecosystem
of Mathura beel.

Water volume consumed for crop irrigation at the plain of Thessaloniki – northern Greece, was
estimated and compared against the volume reported by the General Land Reclamation
Organisation (G.L.R.O.) of Thessaloniki – Lagada. For the estimation of net crop water
requirements, apart from crop evapotanspiration, the contribution of effective precipitation, soil
moisture and the phreatic aquifer through capillary elevation were considered. Estimates were
performed for five collective pressurized irrigation networks (P. Skilitsi, Nisi, Alexandria, Shinas,
Kariotissa), located at the plain of Thessaloniki and referred to years 1995 to 2004 inclusive. River
Aliakmonas is the main source of these networks. Results reveal considerable losses of irrigation
water that are related to the management, operation and maintenance of the networks by the Local
Land Reclamation Organizations (L.L.R.O.).

To describe the tourism potential of an area, not only single meteorological parameters have to be
taken into account, but also thermal sensation and people’s thermal comfort. The latter can be
estimated by the use of human energy balance models and the derived thermal indices, which
comprise all relevant meteorological parameters like air temperature, air humidity, wind speed, and
short and long wave radiation fluxes.
This paper makes an attempt to assess and analyze climatological parameters and the thermal
comfort of Crete, its variations and trends for the period of time 1955-2001. In addition, a definition
and quantification of the island’s tourism potential is carried out.
Long term data from several stations are used from the existing climatic and synoptic network of
Crete, including daily mean, maximum and minimum temperature, relative humidity, wind speed, and
cloud cover over the whole island, in order to derive the daily Physiologically Equivalent
Temperature (PET) and precipitation. In addition, possible trends of thermal comfort and
precipitation on an annual and seasonal basis are analyzed.
Additionally, data of the 10-minutes climatology of the Climate Research Unit of the University of
Norwich have been processed in order to create high resolution (1 km) mean monthly maps for
climatological parameters such as air temperature, precipitation and Physiologically Equivalent
Temperature.

Detailed meteorological data required for the equation of FAO-56 Penman-Monteith (P-M) method
that was adopted by Food and Agriculture Organization (FAO) as a standard method in estimating
reference evapotranspiration (ETo) are not often available, especially in developing countries. The
Hargreaves equation (HG) has been successfully used in some locations to estimate ETo where
sufficient data were not available to use the P-M method. This paper investigates the potential of two
Artificial Neural Network (ANN) architectures, the multilayer perceptron architecture, in which a backpropagation
algorithm (BPANN) is used, and the cascade correlation architecture (CCANN), in which
Kalman’s learning rule is embedded in modeling the daily ETo with minimal meteorological data. An
overview of the features of ANNs and traditional methods such as P-M and HG is presented, and the
advantages and limitations of each method are discussed. Daily meteorological data from three
automatic weather stations located in Greece were used to optimize and test the different models.
The exponent value of the HG equation was locally optimized, and an adjusted HGadj equation was
used. The comparisons were based on error statistical techniques using P-M daily ETo values as
reference. According to the results obtained, it was found that taking into account only the mean,
maximum and minimum air temperatures, the selected ANN models markedly improved the daily
ETo estimates and provided unbiased predictions and systematically better accuracy compared with
the HGadj equation. The results also show that the CCANN model performed better than the
BPANN model at all stations.